Do you have some advice on how to evoke feeling of harshness in the setting without making it caricaturally grim or simply stingy with resources? Something like tolkienesque First Era Beleriand with inaccessible gods and great danger nearby but with less superpowered elves and less focus on nobility?
I think harshness, edginess, or grittiness really lies in the details and how they relate to the overall themes of the campaign.
I would start with the general theme and style for the setting first and then look for points where you can add more sharper edges.